I think if you're close to any airport, it is very normal. If you're, for example, landing in Chicago, I'd be shocked if you can't see a bunch of other planes o

I think if you're close to any airport, it is very normal. If you're, for example, landing in Chicago, I'd be shocked if you can't see a bunch of other planes out of the window. I also once had some delay when having to fly over Dubai, where we had to fly in circles before landing, and I saw a large amount of airplanes circling around the same area above and below us. But I'm no expert in aviation by any means, so I can't really comment on the appropriateness.